1. Field of the Invention
The present invention relates to a base station apparatus in a mobile communication system, and more particularly, to a base station apparatus for increasing the efficiency of the base station to enlarge capacity and service quality of the system.
2. Description of the Related Art
In general, the base station of the mobile communication system includes a radio environment, in which each one of the base stations is composed of one cell. Also, each of the base stations is comprised of different radio environments, according to the construction and shape of the base station, which allows them to accept radio subscribers. There are many different types of base stations such as a sectored base station and an omni-type base station. The sectored base station has three sectored areas partitioned into 120 areas about the base station at the center of a circle. Each area includes equipment such as antennas, etc. Also, the sectored-type base station is classified into stations using 3FA and 1FA, where FA is a Frequency Assignment. Meanwhile, the omni-type base station is constructed to have the whole area in one radius without dividing sectors.
The base station is installed according to the number of mobile communication system users, and hardware for the base station is constructed of one basic frame, which can be extended when the extension of capacity is necessary. Therefore, the base station can be constructed of a basic frame and an extended frame, in which the basic frame and the extended frame have differences as follows:
The basic frame is comprised of a CCB (Common Control Block) for performing an overall control of the base station, a CPB (Channel Processing Block) for performing a channel process and an RFB (Radio Frequency Block). The extended frame comprises additional parts. In other words, the foregoing blocks are installed only in the basic frame, which perform functions including antenna diagnosis, base station control via a PSTN (Public Switched Telephone Network), self-diagnosis and self-test by the base station without assistance of a base station control block, etc. Also, the CPB is extended based on a shelf system, according to the capacity of the base station, and classified into two CPBs: one for accepting 32 channels and the other for 16 channels. The 32 and 16 channel cards can be freely installed and operated within the same shelf, and allows an optimum channel to be constructed, according to the capacity of the base station. Also, one shelf of the CPB can support an omni-6 CDMA (Code Division Multiple Access) carrier, a 3 sector 2 CDMA carriers and a 6 sector 1 CDMA carrier.
Also, the RFB performs signal transmitting/receiving amplification and a front-end function, and has various options which allows the RFB to select and install a front-end module most suitable to the construction of the base station.
In general, the base station includes a duplexer, and needs only two antennas per sector, including a transmission route, and a receiving diversity route. The RPB has a basic configuration, which includes a power amplifier, and can alternatively have a LPA (Low Power Amplifier) or an optic transceiver as optional features without using the power amplifier.
The base station having a cell construction of a 3 sector or 6 sector shape provides more enhanced capacity via sectored gain than using an omni-antenna. In this construction, however, the base station fails to provide an effective interference cancellation. Therefore, the enhanced capacity of the base station cannot be provided as much as a communication provider desires. The base station requires high electric power and thus there is a problem because a high quality service cannot be provided to a subscriber when other subscribers are also transmitting and receiving signals from the base station.
Also, the base station should have different hardware and software, according to the frequency allocated to the communication provider, service type, etc. Accordingly, development cost is increased and resource waste is incurred. While the communication providers are requesting compact sized outdoor base stations with middle capacity, some technical problems have not been solved such as cooling heat generated from the base station, reducing hardware volume, etc. In addition, if a shading area takes place during a service by the communication provider, this problem can be solved by applying relays. Presently, there are no methods available that address the aforementioned problems, which allows a system to solve this problem by itself. In other words, even if one base station frequently shows variation in popularity of the users, change cannot be always carried out, according to channel environment, and thus a problem occurs when the capacity of one base station should be increased. In other words, even if the users are counted within the range that can be accepted by one base station, the ability of each subscriber to use a base station cannot be solved when many users are crowded in one specific sector, and accordingly a problem occurs where the channels of the base station should be increased. Also, there have been problems where the construction of the RPB becomes huge when the output is decreased due to increase of power loss and cost is increased as the system capacity increases.
Therefore, there exists a need for an apparatus and a method that allows a base station to handle an increase amount of traffic from users.